Photoelectrochemical performance of dye sensitized solar cells based on aluminum-doped titanium dioxide structures

Abstract

The present study investigated the photoelectrochemical performance of dye sensitized solar cells (DSSCs) based on aluminum doped titanium dioxide (Al-TiO2) nanoparticles/nanowires (TNPWs) composite photoanode layer, with different electrolytes namely liquid electrolyte, ionic liquid electrolyte, solid state electrolyte and quasi-solid state electrolyte. Al-doped TNPWs composite is prepared through sol–gel and hydrothermal methods. Photoanodes were prepared by coating Al-doped TNPWs composite on indium tin oxide glass plate, and hafnium dioxide (HfO2) is applied over the active layer, which acts as a blocking layer for recombination of charge carriers. DSSCs were fabricated using D149 organic dye sensitizing novel photoanode and different types of electrolytes sandwiched together with cobalt sulfide coated counter electrode. Photovoltaic characteristic study indicates that the DSSC-4 fabricated based on Al-doped TNPWs composite with HfO2 blocking layer and QSSE exhibited enhanced photovoltaic parameters, short-circuit current density, open-circuit voltage, fill factor and power conversion efficiency. The highest power conversion efficiency of 7.26% was achieved in DSSC-4 as compared to other DSSCs. Electron impedance spectroscopy results revealed that the photoelectrochemical parameters, electron lifetime, electron mobility, diffusion length and charge collection efficiency were improved in DSSC-4. These results suggested that the faster kinetics of charge carriers by creation of more traps through Al insertion into TNPWs composite and HfO2 blocking layer model reduced recombination rate of charge carriers by forming an energy barrier at Al-doped TNPWs photoanode/dye/electrolyte interface.